CNN -- Black employees at a Philadelphia, Pennsylvania, waste transfer plant were harassed, humiliated and discriminated against by their supervisor for decades, says an attorney representing two workers who filed a complaint against the city.

Among the allegations in the complaint is that for decades, John Gill, the Northwest Transfer Station's superintendent, limited one restroom to whites only, said the attorney, Howard K. Trubman. The restroom -- which he called the "supervisors' bathroom" -- was supposedly for the sole use of upper-level officials with the city's Streets Department, Trubman said.

As far back as 1996, it became apparent to black employees that they were being slighted, said Trubman. They would watch white co-workers walk into the segregated bathroom, conveniently located one floor above Gill's office.

"If you tried to use the bathroom, you might get suspended," said Leslie Young, a former worker at the facility. Young, along with Gibson Trowery, who still works at the station, filed a complaint with the Pennsylvania Human Relations Commission in October 2007.

Young said he recalled that a lock was placed on the restroom door, with keys distributed only to white workers.

The restroom black workers could use was down five flights of stairs and was "not in the greatest condition," Trubman said. Some employees were forced to ask Gill's permission before they could make the trip, he said.

In May, a Philadelphia judge dismissed a separate suit against Gill, leaving the complaint filed against the city intact.

Trubman said they are seeking Gill's dismissal and monetary damages. He expects a trial to begin by next summer.

The issue didn't end with the bathroom at the facility, which is a transfer station where garbage trucks bring citywide waste to be distributed to various landfills.

Black employees complained that they were stuck with the oldest garbage trucks. Whites, they say, were frequently upgraded to newer vehicles.  Read more.